سه شنبه ۲۷ شهریور ۰۳ | ۱۷:۵۶ ۸ بازديد
eir everyday usage (steady job, uniform distribution, etc.).
The total energy content of a control volume during steady-flow process remains constant
(ECV = constant). That is, the change in the total energy of the control volume during such a
process is zero (DECV = 0). Thus the amount of energy entering a control volume in all forms
(heat, work, mass transfer) for a steady-flow process must be equal to the amount of energy
leaving it. In rate form, it is expressed as =in outE E .
The amount of mass flowing through a cross section of a flow device per unit time
is called the mass flow rate, and is denoted by m. A fluid may flow in and out of a control
volume through pipes or ducts. The mass flow rate of a fluid flowing in a pipe or duct is pro-
portional to the cross-sectional area Ac of the pipe or duct, the density r, and the velocity V
of the fluid. The flow of a fluid through a pipe or duct can often be approximated to be
one dimensional. That is, the properties can be assumed to vary in one direction only (the
direction of flow). As a result, all properties are assumed to be uniform at any cross section
normal to the flow direction, and the properties are assumed to have bulk average values
over the entire cross section. Under the one-dimensional flow approximation, the mass
flow rate of a fluid flowing
The total energy content of a control volume during steady-flow process remains constant
(ECV = constant). That is, the change in the total energy of the control volume during such a
process is zero (DECV = 0). Thus the amount of energy entering a control volume in all forms
(heat, work, mass transfer) for a steady-flow process must be equal to the amount of energy
leaving it. In rate form, it is expressed as =in outE E .
The amount of mass flowing through a cross section of a flow device per unit time
is called the mass flow rate, and is denoted by m. A fluid may flow in and out of a control
volume through pipes or ducts. The mass flow rate of a fluid flowing in a pipe or duct is pro-
portional to the cross-sectional area Ac of the pipe or duct, the density r, and the velocity V
of the fluid. The flow of a fluid through a pipe or duct can often be approximated to be
one dimensional. That is, the properties can be assumed to vary in one direction only (the
direction of flow). As a result, all properties are assumed to be uniform at any cross section
normal to the flow direction, and the properties are assumed to have bulk average values
over the entire cross section. Under the one-dimensional flow approximation, the mass
flow rate of a fluid flowing
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